Choosing the right water turbine for a hydropower plant is a critical decision that impacts the plant's efficiency, cost-effectiveness, and overall power generation. Several factors must be carefully considered to ensure optimal performance. The question asks us to identify an incorrect factor for selecting a water turbine.

Water Turbine Selection Factors

Let's examine the common factors that influence the selection of a water turbine in a hydropower plant:

• Height of Head: This refers to the vertical distance between the water level in the reservoir and the turbine. The height of the head is a primary determinant of the type of turbine used. For example, high heads typically use Pelton turbines, medium heads use Francis turbines, and low heads use Kaplan turbines.
• Discharge Rate: Also known as the flow rate, this is the volume of water flowing through the turbine per unit of time. The discharge rate is crucial because it directly affects the power output of the turbine. Different turbine types are designed to handle different ranges of discharge rates efficiently.
• Output and Nature of Load: The required power output of the plant and the variability or steadiness of the electrical load it needs to serve are important considerations. This helps determine the size and number of turbines, as well as their speed regulation capabilities. A plant designed for base load operation might prioritize efficiency at constant output, while one for peak load might need quick response times.
• Heat of Water: The temperature or "heat of water" is generally not a primary factor in choosing the type of water turbine. While extreme water temperatures could theoretically affect material properties or cavitation slightly, the specific type of turbine (Pelton, Francis, Kaplan) is primarily selected based on the available head and discharge, not the water's heat. The operational temperature range of water in most hydropower applications does not significantly influence the fundamental hydraulic design or selection of the turbine itself.

Detailed Analysis of Factors

To further clarify, let's look at why each factor is relevant or irrelevant for water turbine selection:

1. Height of Head:

• The height of head is perhaps the most important factor. It determines the potential energy of the water available to drive the turbine.
• High Head (over 200m): Pelton turbines are typically chosen for high head and low discharge sites.
• Medium Head (30m to 200m): Francis turbines are suitable for medium head and medium discharge conditions.
• Low Head (below 30m): Kaplan turbines (or propeller turbines) are ideal for low head and high discharge sites.

2. Discharge Rate:

• The discharge rate, or the volume of water flowing per second, directly relates to the power generated.
• A high discharge rate with a low head favors Kaplan turbines.
• A low discharge rate with a high head favors Pelton turbines.
• Francis turbines handle a broad range of discharge rates and heads.

3. Output and Nature of Load:

• The desired electrical output capacity of the power plant dictates the size and number of turbines.
• The nature of load (e.g., constant base load, fluctuating peak load) influences the turbine's design, particularly its speed governing system and ability to operate efficiently over a range of power outputs.

4. Heat of Water:

• The "heat of water" or water temperature does not play a direct role in determining the fundamental type of water turbine to be installed. The design of the turbine is based on fluid mechanics principles related to head and flow, not the thermal properties of the water.
• While extremely cold water might have slightly higher viscosity or warmer water could slightly increase cavitation risk, these are usually minor considerations that don't change the basic turbine choice based on head and discharge. Therefore, it is an incorrect factor for choosing the water turbine type.

Based on this analysis, the "Heat of water" is the factor that is INCORRECT for choosing a water turbine in a hydropower plant.